Blight
by Aini NuFire
Summary: When an angel leaves a vessel, it leaves a little bit of grace behind. So when Amara ripped Lucifer out…what did that mean for Cas? With the Devil's cancerous grace eating away at Castiel's, can the Winchesters find a way to save their angel? S12 one shot


**A/N: Just another "what if" idea I had. I mean, the show sets these precedents, but then doesn't follow through on them. This one shot got loong though. And the ending was kinda unexpected, hah. Takes place after 12x3 "The Foundry."**

 **Disclaimer: Don't own** ** _Supernatural_** **. Thanks to 29Pieces for beta reading!**

* * *

"Blight"

Given how many times Castiel had worked with Crowley over the years, another necessary though begrudging team up shouldn't have surprised him. And yet he couldn't believe he was currently sharing a motel room with the ousted King of Hell while they hunted Lucifer together. To quote Metatron, it was like being in a buddy comedy, without the buddy.

Castiel was scrolling through news feeds on his phone, trying to find any hint that Lucifer had made his way back from the bottom of the ocean, but he was having difficulty concentrating with Crowley watching television in the background.

At another raucous chorus of laughter from whatever studio audience show was currently airing, Castiel set his phone down harshly. "I thought we were supposed to be looking for Lucifer."

Crowley didn't even glance away from the television as he responded, "Yes, well, until he drags himself up from the bottom of Davy Jones's Locker and finds a new vessel, we don't exactly have anything to go on, do we?"

Castiel rolled his eyes in growing annoyance. "And I'm searching for signs that he's already done so. What are you contributing?"

Crowley waved a dismissive hand. "I have feelers out. As soon as Lucifer shows himself, I'll be alerted."

Castiel scowled, and reached up to pinch the bridge of his nose; he felt another headache coming on. They'd been getting progressively worse over the past few days, and Castiel had been attributing it to Crowley's obnoxious presence. But now there was a growing nausea in his stomach and a pain in his chest. From his brief time as a human, Castiel had become acquainted with a scant handful of illnesses, and knew how to recognize when something was wrong. He didn't understand what could be affecting him now as an angel, though.

Perhaps it was psychosomatic from being around the demon for a prolonged period. He probably just needed some air.

Castiel rose from his seat, intending to head for the door, but pain suddenly exploded in his chest, and he bent double with a harsh gasp. One hand caught himself on the edge of the table, the other clutching at his heart. What was happening? Had a spell been cast on him? Had Rowena…?

Castiel sucked in a sharp breath and tried to regain control of himself. The pain was already abating. Whatever it was, he could get a handle on it.

Crowley got to his feet and started eyeing Castiel warily. "What's wrong with you?"

Castiel managed to lift his head enough to direct a baleful glare at the demon. "I'm fine," he gritted out.

Crowley frowned as he scrutinized him. "I beg to differ. Actually…there is something different about you."

Castiel's breathing slowed, and he tentatively straightened, bracing for another wave of pain. It had passed, though, leaving only an uncomfortable sloshing in his stomach and the drum beats behind his eyelids.

"What do you mean?" he asked, dread curling through his insides and making the queasy feeling worse.

Crowley tilted his head in consideration and moved closer. Castiel wanted to recoil as the demon raised a palm toward him, but he held himself rigid. Crowley currently needed his help, and wouldn't do him any harm. The demon's eyes narrowed.

"There's something lurking underneath your power signature. Something…dark." Crowley lifted his eyebrows. "Interesting."

Castiel instinctively took a step backward, panic threatening to overwhelm him. There was something inside him? But that wasn't possible. Lucifer had been evicted by Amara, and Castiel had his own grace, not another angel's…

He nearly staggered as realization struck. _Grace_. When an angel possessed someone, they left a little bit of their grace behind after vacating the vessel. That meant…

Castiel prayed it wasn't true as he closed his eyes and focused his senses inward. The motel room with the television in the background and its stale odors muted down to nothing until there was only the small, steady thrum of angelic energy. It was smaller than it once was, pulsating like a candle flame instead of the neutron star it used to be. Metatron's spell to cast the angels out of Heaven had left only a trickle of Castiel's original grace. But it was his and he was able to function on it.

He concentrated harder, delving deeper into the ebb and flow of celestial essence. The throbbing in his head increased. There was a spritz in the angelic force, and Castiel tuned his senses toward it. A thread of grace was vibrating at a different frequency. Curious and a little unnerved, Castiel reached out to brush lightly against it. He nearly crumpled in searing pain as the strand sent a jolt of electric red through him. It scorched with fiery vengeance, just like…just like when Lucifer had been possessing him and the Devil's grace had been burning him out.

Castiel stumbled, the backs of his legs hitting the chair, and he sank into it with a thud. He had some of Lucifer's grace still inside him. But unlike when Sam had a bit of Gadreel's, this remnant wasn't dormant and harmless. Castiel could feel it now—the insidious tendrils worming their way throughout Castiel's own grace, eating away at it like a cancer. And, given his less than pristine state, Castiel's grace would likely not be able to fight off such an evil taint forever.

He didn't know what would happen to him if the malignancy was to spread and completely consume him. Would he be burned out? Or…or would he be…changed? Corrupted into something unclean and evil? Would he become the new Lucifer in more than just name?

A lump began forming in his throat, threatening to cut off his air supply, which he had never needed before. He was already different: not quite human, but no longer completely an angel. It was why Lucifer had been able to possess him in the first place.

Crowley was staring at him expectantly.

"It- it's Lucifer's grace," Castiel said hoarsely. "He left a piece behind when he was ripped out."

Crowley arched an intrigued brow. "Really? That is interesting. Perhaps we can find a way to use that."

Castiel swallowed hard. There was a way… "We can. There's a spell to track an angel through his grace."

"Hm, handy," the demon mused. "What do we need?"

Castiel forced himself to stand. He could do this. It was dangerous, and would be excruciating, but he had no choice. He would not allow the Devil's taint to corrupt him.

"We'll need Rowena," he said. "We'll have to extract the grace for the spell. I need to return to the Men of Letters bunker to retrieve the supplies."

Crowley narrowed his eyes a fraction. "Extract the grace? That doesn't sound pleasant. How do you plan to extract Lucifer's and not your own?"

Castiel didn't answer, and Crowley let out a soft snort.

"You can't, of course. Bollocks, can't you ever just keep your grace in working order?" he said with an exasperated sigh.

Castiel leveled a dark glower at him. It wasn't like he'd expected this to happen. In truth, he hadn't expected to survive Lucifer's possession in the _first place_.

"Very well. Perhaps Mother will have a solution for that." Crowley pulled out his phone, presumably to give Rowena a call. "You get the supplies we'll need and meet back here."

Castiel didn't bother with a response, just turned and left the room. He didn't want to entertain the idea that Rowena might be able to work a solution for his grace being tangled with Lucifer's. Because chances were, that wasn't likely. And at least Castiel's last act would be to contribute to putting Lucifer back in his Cage. He had to hope that would be enough to earn him redemption.

* * *

Castiel drove through the night to reach the bunker. It'd been three years since he lost his wings, and still he missed them, including the convenience of traveling from one place to another in an instant. He'd felt the vague sensation of flying while under Lucifer's power, as the Devil's wings had still been intact. It had stirred a longing in him…and guilt, when Lucifer reveled in the fact that every other angel's wings had been clipped in the Fall as well.

It was still early when Castiel entered the bunker. He didn't hear Sam or Dean up and about. Which was probably best; perhaps Castiel could get in and out without disturbing them.

He went straight to the library and started scouring the records for the journal they'd used to extract Gadreel's grace from Sam. He also needed to find that syringe device. He was so intent on his search that he didn't notice when Dean emerged from the corridor.

"Cas? What are you doing?"

Castiel barely flicked a glance at the hunter. "Looking for something."

Dean snorted. "I can see that. Anything in particular?"

There was an odd tightness in his voice, and it took Castiel a moment to remember that Dean had once walked in on Lucifer ransacking the place under Castiel's guise.

"I'm not possessed," he said, turning to face Dean. "I wouldn't do that again."

Except…he might. If Lucifer's grace twisted him enough, who knew what Castiel would be capable of doing…

Dean didn't look reassured. _Good_. He needed to be on his guard.

What the hunter said, though, was, "I know. Plus, you're still wearing the coat."

Castiel frowned, not understanding. Why would he not be wearing his coat?

"I thought you were working with Crowley to hunt Lucifer," Dean went on.

"I am." Castiel turned back to his search. "And then I remembered the Men of Letters had a spell to track an angel, which is what I'm looking for."

"Seriously? Why haven't I heard this?"

"You weren't here when Sam and I attempted to use it for Gadreel," Castiel replied. He opened a box that looked familiar, and sure enough, the grace extractor was inside. The needle seemed larger than Castiel remembered.

Swallowing nervously, he set the box aside and continued searching for the journal that contained the ingredients and procedure for the spell. Castiel thought he might remember it, but with something so crucial on the line, he wanted to be certain.

Dean picked up the box. "Jeez, what the hell is this for?"

Castiel didn't answer. He didn't really want to explain the process, particularly because he didn't want to freak himself out beforehand; he remembered just how excruciating an ordeal it had been for Sam.

Speaking of which, Castiel vaguely heard the other Winchester's footsteps enter the library.

"Hey, Cas. When did you get in?"

Castiel ignored him. The sooner he found the spell, the sooner he could get this wretched, parasitic grace out.

"Uh, Cas?" Sam tried again after a moment.

Dean snorted. "Dude's on a mission. Said there's a spell we can track Lucifer with."

"What? How?" There was a brief silence, and then Sam sucked in a sharp breath. "Wait, _this_?"

"What's wrong?" Dean instantly demanded.

Castiel closed his eyes for a moment, and then turned to face the brothers. Sam was staring at him in wide-eyed horror.

"There's some of Lucifer's grace left inside you?" the younger Winchester asked in a hushed voice.

Dean's brows shot upward and now he looked equally as panicked. "Wait, what?"

"It happens when an angel leaves a vessel," Castiel hurried to explain. "Sam had some after Gadreel, and we removed it to try this tracking spell. We didn't have enough grace at the time, though." Which wouldn't be a problem in this case. Castiel had backed off from the extraction when it had started to kill Sam; this time, he'd be removing it all.

Dean continued to gape at him, then at the syringe in Sam's hands. "So, you're gonna _extract_ Lucifer's grace in order to cast a tracking spell?"

"Yes."

"Cas," Sam sputtered. "How are you going to extract Lucifer's grace and not yours?"

Castiel clenched his jaw. Dammit, this was what he'd been hoping to avoid.

Dean's eyes hardened with anger. "You're going to rip out your grace? What the hell are you thinking?"

"That this is our best shot at finding Lucifer and getting the jump on him," Castiel rejoined.

"Cas," Sam broke in again, sounding distressed. "The extraction process nearly killed me. If you don't have your grace, it could kill you, too."

Dean shot a horrified look at his brother, then whipped back to Castiel. "What exactly is the plan here, Cas? You remove the grace, separate them, and take yours right back?"

Castiel looked away, unable to meet their eyes. "I- I don't know of a way to separate them." He hesitated. "…Rowena might be able to."

Dean's expression morphed into incredulity again. "Rowena? Oh that's just fantastic."

Sam's mouth pressed into a tense line. "Cas, aren't you kinda jumping the gun here? Shouldn't you wait until we actually have a spell to separate the grace?"

Castiel's chest constricted. If only he had that kind of time. He didn't _want_ to die, not really. At least, not before he'd fully cleaned up his mess with releasing Lucifer. Dying now, even if his extracted grace would be useful for tracking the Devil, would still leave his penance unfinished and the burden on others to follow through on.

"Lucifer's grace…" he started, and then had to swallow around a lump in his throat. "It's eating away at mine," he finished grounding out. "I- I don't know how long I have before it will consume me."

Sam and Dean exchanged horrified looks, and Castiel felt a pang in his heart for having to burden them with this when they had so much else to deal with.

Dean squared his jaw. "Alright, call Crowley and tell him to get Rowena's ass over here, right now."

Sam surged into action as well, setting the syringe on the study table and moving to the catalog cabinet. "The Men of Letters had a spell for tracking an angel through grace; maybe they have something about separating ones that are entangled."

Castiel blinked, stunned. He wanted to protest that he and Crowley could handle this…but there _were_ more resources in the bunker, and if that would increase the chances of success for this endeavor, then perhaps he should stay and accept their help.

He slowly pulled out his cell phone and sent a text to Crowley, now that the King of Hell was in his Contacts, explaining the change in plan. A moment later, his phone pinged with a reply.

 _"Why am I not surprised?"_

Castiel assumed that meant the demon was onboard, and he tucked his phone back in his pocket, then resumed his search for the tracking spell. That was, after all, the priority.

* * *

Sam turned the last page in the journal he'd been reading, and let it flip closed with a sigh. So far, they weren't finding anything about how to separate angelic essences from one another.

Dean shoved himself away from the study table abruptly. "Gonna make some more coffee," he grunted, getting up and heading for the kitchen.

Sam cast a sympathetic look at his brother's retreating back. At this point, they were counting on Rowena for a save, and no one was happy about that.

Sam glanced over toward where Cas was going through another bookshelf, and frowned when he spotted the angel bowed forward, the knuckles of one hand white around the edge of the shelf as he held himself up, the other clutching his chest.

"Cas?" Sam surged from his chair and hurried over. "Hey, you okay?"

Cas's jaw was clenched tightly, and he looked as though he were riding out a wave of pain. After a long moment in which Sam was starting to freak out, the lines of his face eased slightly, and Cas staggered.

"I'm fine," he rasped.

"Yeah, I don't think so. Here, sit down." Sam grabbed his elbow and guided him to the closest chair. Cas practically collapsed into it. "Is it Lucifer's grace?" Sam asked worriedly.

Cas's throat bobbed, and he gave a slow nod. "I don't know how much time I have left."

Sam's heart dropped into his stomach. "Just hang on, okay? Crowley should be here soon." _He'd damn well better be_.

Cas lifted his head to meet Sam's gaze. "Sam, we have to extract the grace."

He shook his head. "Not until we have a way to restore yours, or you'll die."

"I'm dying already," Cas huffed out, and then grimaced. "Sam, please. I…I don't want this… _evil_ , in me anymore. If I'm going to die, if there's any _chance_ of earning redemption…this taint, if I'm corrupted any further…"

"That is not going to happen to you," Sam interrupted.

Cas made a strangled noise in the back of his throat. "You don't know that. This is _the Devil_ …"

"And I'm supposed to be his true vessel." Sam's gut clenched in sympathy at the utter terror in Cas's eyes. "And I used to think I was somehow unclean and damned because of it." He still remembered the Trials to close the Gates of Hell, how they had felt like they were purifying something deep within him that he could never hope to reach on his own.

"But I know now that's not true," he continued. "And Lucifer's grace eating away at yours is not going to damn you, Cas. For one thing, we're _going_ to fix it."

Cas shook his head in frustration. "If there's even a _trace_ left, Sam, I don't want it back. I _can't_ —"

A deep, resounding banging on the door echoed through the bunker. Sam tensed automatically, and listened as Dean's footsteps clomped up the stairs to answer. A moment later, he returned with Crowley and Rowena in tow.

"You know what's going on?" Dean asked as he led them into the library.

"Castiel here has a wee bit of archangel grace leftover from Lucifer's residence," Rowena replied with an unaffected air as she flicked her gaze over the angel. "And you have a spell that can use it to track him."

"Yeah, but we need to separate Cas's grace from Lucifer's," Dean said.

"Hmm." She pursed her mouth into a thoughtful moue. "I don't have a spell for that, but I do have one that will take that teeny tiny bit of Lucifer's grace and turn it into a weapon against him."

Cas pushed himself out of his chair. "What do you mean? What kind of spell?"

Rowena lifted her chin smugly. "A nasty little casting I picked up from the Book of the Damned. Basically, it channels the connection between a piece of one's essence and themselves, and then detonates them both."

Crowley arched an eyebrow. "Well, that sounds promising. What are we waiting for?"

Sam shot a hand up. "Hold on, what about Cas's grace?"

Rowena looked directly at Castiel, her expression sobering. "Since your grace is enmeshed with Lucifer's…it will destroy you as well."

Silence fell over the room with that proclamation.

After a long moment, Cas drew his shoulders back and said, "Destroy it," just as Dean said, "Then no way."

Cas glared at him. "Dean, we have a chance to destroy Lucifer once and for all.

Dean glared back incredulously. "I'm sorry, did you miss the part about it killing you too?"

"This is _Lucifer_ ," Cas pressed. "Stopping him is more important."

"I have to agree with Castiel," Crowley spoke up.

Both Sam and Dean shot the demon a scathing look.

"You don't get a vote," Dean snapped.

Cas took a step forward. "There's no vote because this is my decision."

Dean whirled back to him. "Not when you're deciding to _kill_ yourself!"

Sam felt the static suddenly rise on the air, tingles running up his arms and the back of his neck. He could almost see Cas's energy crackling beneath the surface.

"I won't let it turn me!" the angel exploded, eyes blazing with an intensity Sam rarely saw from him. "Lucifer's grace is consuming mine, and I don't know if it will simply burn me out, or if it will change me. But I can't take that chance. I've been evil before, Dean. Consumed by the souls from Purgatory, by the Leviathan. I know what it's like to be surrounded by Lucifer's pure evil, and I _won't_ let myself become something that could destroy the world again. So either remove the grace or put an angel blade through me!"

No one moved, too stunned to speak. Dean's jaw was hanging slack, his eyes wide with horror. Sam couldn't breathe.

Cas suddenly swayed, his eyelids fluttering rapidly. Then he stumbled and collapsed to his knees.

Sam leaped forward to catch him, grabbing his arm and holding him up before he could hit his head on the concrete floor. He shifted so Cas's head lolled back against his shoulder, and his heart leaped into his throat at the sight of blood leaking from Cas's nose.

"Shit, guys, I don't think we can wait."

"You said the extraction could kill him!" Dean shouted, dropping down next to them.

"This _is_ killing him." Whether they liked it or not, Lucifer's grace had to come out, _now_.

"I can whip up a hex bag," Rowena put in. "Something to keep him alive for a little while at least."

Sam nodded sharply. "Do it." That was all they had. "Dean, help me get him to the infirmary."

Dean's face pinched, obviously still against this, but he didn't argue, and slid an arm under Cas's back.

"Crowley, grab that box," Sam said, thrusting his chin toward the syringe on the table. Together, he and Dean hefted Cas up, and started dragging him toward the infirmary on the other side of the library. Once inside, they settled him in the examination chair. Cas's breathing was hitched, and he kept wincing as though each one caused him pain.

"What do we do?" Dean asked.

Sam turned to Crowley and took the syringe from him. Memories of unbelievable, indescribable agony filtered up from the depths of his mind. Oh god, how was he supposed to do this?

Cas flailed his hand to weakly grasp Sam's wrist, and for a moment Sam thought he had changed his mind, that he'd try to hold on a little longer.

But Cas just gave him a faint a smile and nodded. "It'll be over soon, Sam. Lucifer will never threaten you again."

A spiky lump gathered in his throat, and Sam swallowed hard. He leaned down to whisper in Cas's ear, "Don't you dare give up on us."

Cas didn't respond, but flinched as a violent shudder ripped through him, and a groan caught in his throat.

Sam couldn't believe he was about to do this. "Dean." He glanced up long enough to grimly meet his brother's eyes. "Hold him." And then Sam angled the needle down and inserted it under Cas's jawline.

Cas gritted his teeth and choked back a cry, but his body still jerked in reflex. Dean gripped his shoulder and planted the other arm across Cas's chest. Sam took a deep breath, knowing that wasn't even the worst of it, and steadied himself to pull back the plunger.

"Crowley," he growled. "Watch his vitals. We can't let his heart give out before Rowena finishes that hex bag."

"Can't you heal him?" Dean snapped at the demon.

Crowley scoffed. "If you wanted to make a deal of some kind, maybe. But handing out miracles like candy doesn't come with the demonic package."

Sam gritted his teeth and tuned them out. His whole focus narrowed on the massive needle poking up into the bottom half of Cas's brain, and the fizzy blue light starting to trickle into the barrel of the syringe. He started to pull the plunger back.

Cas screamed, and Sam froze as not only blue, but fiery red spilled into the barrel. Lucifer's grace. It curled and writhed around Cas's, blackness along the edges that sizzled and charred the silvery striations in Cas's pure, sapphire essence. Sam suddenly felt sick to his stomach, and understood why Cas was so afraid of the Devil's taint changing him. Sam could see Lucifer's grace devouring Cas's, one wisp at a time, slowly withering a strand until it curled into a blackened, shriveled root, only to get absorbed into the molten red.

A thrill of terror surged through Sam, and he pulled back on the plunger again, eyes watering under Cas's screams. But he needed to get that poisonous grace out, _all_ of it out.

Cas shuddered under Dean's hold, and fresh blood started streaming from his nose.

"Hang on, Cas, I got you," Dean said, over and over again. "I got you."

"Easy, Moose," Crowley interjected.

Sam forced himself to slow down. Where the hell was Rowena?

Heels clacked on the floor, and a second later she appeared, a dark green pouch in one hand. "Here," she said, holding it out. "Put it under his head."

Crowley took the hex bag and moved to Cas's head. Sam steeled himself, and pulled the plunger the rest of the way. The last bit of azure and scarlet grace trickled into the barrel, and Cas fell limp. Sam withdrew the needle.

"Cas?" Dean's voice cracked.

Crowley placed the hex bag behind Cas's head, and then paused to study him. "Well done, Mother, he's hanging on by a thread."

Sam's heart was pounding against his rib cage and he couldn't seem to make his hands stop shaking. The two graces in the syringe swirled around and around each other, twining about like one huge Celtic knot. Sam turned toward Rowena and started to hold it out, only to stop and tighten his grip.

"Find a way to separate the grace," he said. He didn't need to voice the threat implicit in his tone.

Rowena gazed up at him for a solemn moment, and then nodded.

* * *

Dean sat on one of the lab stools in the infirmary that he'd pulled up next to Cas, who was still unconscious in the exam chair. Everyone else had gone back out to the library to search for a way to separate Cas's grace from Lucifer's. But since research was never really Dean's strong-suit, and Cas needed someone to stay with him, Dean was fine not moving from this spot.

Except that watching his best friend barely clinging to life carved out a pit in Dean's stomach and filled it with glass shards. How had they ended up at this place, _again_? They'd just gotten Cas back, for crying out loud. Lucifer had been evicted, the Darkness was gone and the world was saved, Mom was alive again…things were supposed to be _okay_.

But it never was in the Winchesters' lives. Maybe it was good that Mary had left. And maybe it was better if she did just stay away. Sam and Dean were cursed, and they brought nothing but pain and death to those in their lives. How many times had Cas almost died since knowing them? Or _actually_ died?

And this? Dean was going to have nightmares of Cas's guttural screams and that sinister vermillion grace pulsing like a beating heart while Cas's sparkling blue sputtered underneath it.

Dean tried to shake the image off, and grabbed a cloth from the tray to wipe a spot of blood from Cas's nose that he'd missed before. Cas's face scrunched up, and he let out a low moan.

Dean dropped the cloth back on the tray and leaned in. "Cas? Can you hear me?"

Cas's eyelids fluttered, and after an agonizingly long moment, finally opened.

"Hey," Dean breathed. "How you doin'?"

Cas gazed at him for several seconds, pupils slightly cloudy. "I feel…everything," he finally wheezed. "And it hurts."

Dean's stomach clenched. "I bet it does." He didn't even want to think about Sam having gone through this same process, though it sounded as though at least Cas had been able to heal him instantly. "Just hang in there."

Cas let out a raspy sigh. "I don't want to be human again."

Dean frowned. "Hey, I thought we weren't so bad?"

Cas squeezed his eyes shut with a grimace, a small whimper catching in his throat.

Dean took his hand and held it tightly. "Don't worry, Cas. The others are looking for a way to save your grace, so you don't have to be human again."

Cas's eyes snapped open, chest hitching. " _No_. You need to cast that spell to destroy Lucifer."

"Lucifer isn't going anywhere," Dean replied sharply. "And neither are you. So shut up and stop trying to die on us."

Cas started shaking his head. "Dean, I don't want my grace back if there's even a _speck_ of his. I can't go through this again."

Dean squeezed his hand reassuringly. "We'll make sure there isn't, I promise. I'm not gonna let this destroy you, Cas. I can't lose you, not after everything. I can't lose anyone else."

Cas's eyes turned sympathetic, despite the pain still swirling in their depths. "Mary _will_ come back. You have your family, Dean."

" _You're_ my family." _Son-of-a-bitch_ , how many times did he have to say it?

Cas gazed at him sadly. "I barely belonged as a broken angel; I certainly never belonged as a broken human."

Dean's throat constricted. "That is not true. You do belong here, with me and Sam. And I am so damn sorry I never realized that you ever doubted that." Maybe if he had, Cas never would have said yes to Lucifer in the first place.

Cas tensed up, micro tremors running through his muscles. His hand was cold in Dean's as shock kept setting in. Rowena's hex bag was holding it at bay, but barely.

"It's…nice to hear," Cas said, voice trailing off as he lapsed back into unconsciousness.

Dean's heart nearly seized, but then he noticed Cas's chest was still rising and falling with shallow breaths. But dammit, they were running out of time.

He gave Cas's hand one last squeeze of strength, and then strode out of the infirmary to check on everyone's progress. As he came around the corridor, he heard raised voices in the library.

"You're letting your sentiment overrule logic, Moose," Crowley said, voice an octave higher than normal.

"You don't even need to be here," Sam retorted, just a hair below full on shouting. "In fact, why don't you leave before I stab you in the throat?"

"Whoa, whoa, whoa," Dean interrupted, sweeping into the room. "What the hell is going on? You're supposed to be looking for a way to save Cas!"

Sam's nostrils were flaring as he seethed at Crowley. The King of Hell looked no more calm, cheeks slightly red as he rolled his eyes. Rowena was standing at the other end of the table, oddly quiet. Dean raised his brows at her in demand of an explanation.

"I came up with a spell to purify Castiel's grace," she began. "It would completely remove Lucifer's essence from his."

Dean shot dubious looks at Sam and Crowley. "Okay, great."

" _However_ ," Rowena went on. "Only one spell can be done. There's no way to separate the grace. Either we purify it—or destroy it."

Dean took a moment to process that. Okay, so their shot at the Devil turned out to be too good to be true. What else was new? He narrowed his gaze at Sam and Crowley. No way was this even debatable…

Crowley let out an exaggerated sigh. "Look, I'm not trying to be the bad guy here. _Lucifer_ is the bad guy. And this is clearly what Castiel wants. We should respect his wishes."

Dean was momentarily too stunned to even think about punching the demon.

Sam, however, had obviously gotten riled up already. "Cas doesn't have to die! And we can find another way to stop Lucifer."

"Yes, because all our efforts have worked so well in the past," Crowley retorted. "You planning on jumping in the Cage again?"

Dean turned toward Rowena. "Purify it."

She arched a delicate brow while Crowley spluttered in the background.

"You're throwing away our best shot—"

Dean drew his gun and aimed it at Crowley's head. "I will shoot you in the face if you don't shut it. Cas is family, and we are not sacrificing him for this. There's always another way, and we'll find it." He nodded sharply to Rowena. "Purify it."

She dipped her head in acknowledgement, and then picked up the syringe full of crackling grace. She pulled the plunger out, and tipped the barrel over so the grace could slide out into a wooden bowl. Dean watched, riveted, as the two opposing energies writhed and contorted around each other. Cas's azure essence seemed smaller than the Devil's raging inferno. Dean hoped the witch could actually do what she claimed.

Rowena threw a pinch of some powder into the bowl and began to chant in Latin. The grace spat and hissed like flames, and an orange singe glowed around the edges of the bowl. Rowena grabbed a fistful of some other ingredient, an herb, maybe, and tossed that in next. The litany rolled off her tongue in deep, booming intonations, and the grace gurgled and roiled more turbulently. Dean exchanged a worried look with Sam.

The bowl, and therefore the table, juddered as the spell ignited. Rowena raised her voice to a shout. Purple magic spewed up from the bottom of the bowl, enveloping both Lucifer's and Cas's grace. It twisted and turned, and then a spot of gold burst through one point, then another. Brilliant beams of blazing light cracked across the inky surface, and finally exploded in a flash of gold.

Dean threw his arms up to cover his eyes. The light instantly dimmed, and he looked back to find dazzling blue grace sloshing in the bowl, no sign of malignant red.

"It worked?" Sam gasped.

"And there's no chance a little of Lucifer's survived and is still in there?" Dean checked.

Rowena held her chin up. "It's good as new."

Dean snatched the bowl up and turned to rush back to the infirmary, Sam on his heels. They reached Cas's side, the angel still unconscious and deathly pale. Dean hesitated, not sure how this worked.

"Pour it in his mouth," Crowley huffed from the doorway.

Dean glanced at his brother, and then tipped the edge of the bowl toward Cas's lips. The grace flowed in like liquid, and Cas's chest immediately began to glow. The gold aura quickly spread across his body, growing brighter. Dean and Sam staggered back several steps. Cas's eyes shot open, blazing blue like radioactive orbs. Dean felt such immense relief.

And then Cas screamed.

The light within him surged, sending out a shockwave that propelled Dean and Sam back further. They both threw their hands up as the temperature shot up and the air fizzled.

Crowley frantically tried to cover his eyes. "What did you do?" he shouted at Rowena.

"I don't know!" she shrieked back. "It's not like I ever tried this spell on an angel before!"

Dean couldn't even muster the anger to yell at the two of them, for all he felt in that moment was terror that Cas was dying some horrendous, excruciating death. Had Rowena tricked them? Had she cast the spell to destroy Lucifer, and the Devil was going up like a supernova, just like Cas was now?

Cas bolted upright and tumbled out of the chair, landing on his knees on the floor. His back arched with another scream, and the shadows of broken wings arced across the wall. Dean couldn't breathe, couldn't move. He wanted to run to his friend, to grip Cas's arms and wrench him back from the edge of this horror.

The wings snapped taut with a crackle on the air, and Dean froze, unable to look away as the appendages shuddered. And then something started sprouting from the bare bones. For a long moment, Dean couldn't even comprehend what he was seeing. It wasn't until the shadows started filling out with feathers that he gasped in understanding.

All Dean had known since the Fall was that the angels' wings had been clipped. He had no idea that meant broken and battered to the extent he saw now, right in front of him. Yet another pain Cas had endured in silence.

Now, though, now feathers were growing back with ferocious intensity, and no wonder Cas was screaming as brittle bones snapped back into place. Even Dean heard them.

It seemed like it went on forever, but at long last, the wings gave one final flap, lush and fully restored, and then the light blazing inside of Cas dimmed down to nothing, and he collapsed forward onto his hands and knees.

"Cas!" Dean ran forward and dropped down beside him. Sam skidded over to Cas's other side. "Cas?"

Cas's entire body was heaving with labored breaths, but he managed to lift his head, eyes wide in stunned shock.

"Hey, man, say something, please," Dean begged, because he was still freaking out over what just happened.

"I-I'm," Cas stuttered. He craned his neck to look behind him, even though his wings were invisible or on the ethereal plane or whatever. " _How_?"

"You're welcome," Rowena piped up.

Castiel blinked up at her in stupefaction. "You did this?"

"She purified your grace," Sam explained. "Though I guess she did a little more than that." He shot her an accusing look.

Rowena lifted her chin haughtily. "You wanted restoration, that's what I did. I didn't realize Castiel's grace was already in a sore state by itself." She hummed smugly and raised a hand to examine her manicure. "The Grand Coven should be groveling at my feet for me to return to them."

Dean rolled his eyes.

Cas kept glancing between them all dazedly. "And- and Lucifer?"

Dean shook his head. "He's still on the to-do list."

Cas gaped at him for a second before his expression hardened. "Dean, you didn't—"

"I did, and I'd do it again," he interrupted unapologetically. "Every time. You're our brother, Cas. And me and Sam aren't gonna let you forget it."

"But Lucifer—"

"We'll get to him," Dean said. "Us here," he gestured to all of them, even Crowley and Rowena, "we can handle it." He nodded to Sam, and the two of them took Cas's arms and hauled him to his feet. The angel still seemed a bit stunned, so they didn't let go right away.

"Cas?" Sam pressed. "How do you feel?"

Cas blinked at him owlishly. "I feel… _whole_. And my wings…"

Dean couldn't help but smile at how awed and grateful he sounded. They had never had such a win before, and it felt damn good.

Maybe being part of the Winchester family wasn't a curse after all. Or maybe the curse was that once a member of that family, they never let go.

And he could think of worse ways to live.


End file.
